3-Aryl-5,6-dihydro-1,4,2-oxathiazines and their oxides

ABSTRACT

Disclosed are derivatives of 3-aryl-5,6-dihydro-1,4,2-oxathiazines and their oxides for use as herbicides, fungicides, plant dessicants and defoliants in agricultural and biocidal applications. Also disclosed are methods of making these compounds.

This is a continuation-in-part application of U.S. patent application,Ser. No. 425,739 filed Sept. 28, 1982, now abandoned.

This invention relates to derivatives of3-aryl-5,6-dihydro-1,4,2-oxathiazines and their oxides, and to the useof such derivatives as herbicides, fungicides, and plant dessicants anddefoliants. The invention also relates to methods of preparing thesechemicals.

Dihydro 1,4,2-oxathiazines are little known in the chemical literature.A multi-substituted compound,N-(5,6-dihydro-5,6-dimethyl-3-phenyl-1,4,2-oxathiazine-6-yl)acetamide,was reported in Tetrahedron Letters, 1972, p. 5267, and a tetrahydrocompound was described in J. Org. Chem. 30:949 (1965). However, noutility was disclosed for these compounds.

The chemicals of this invention are represented by the general formulaebelow, and possess herbicidal activity, fungicidal activity and plantdesiccating and defoliating activities. ##STR1## wherein n is 0, 1 or 2,R¹ is hydrogen, C₁ -C₄ linear or branched alkyl or benzyl, and R has oneof the following values:

phenyl or naphthyl;

phenyl substituted with 1 or 2 of the following groups:

hydroxyl

halo

C₁ -C₁₂ alkyl

C₅ -C₆ cycloalkyl

trihalomethyl

phenyl

C₁ -C₅ alkoxy or alkylthio

tetrahydropyranyloxy

phenoxy

C₂ -C₅ alkylcarbonyl

phenylcarbonyl

C₁ -C₄ alkylsulfinyl

C₁ -C₄ alkylsulfonyl

carboxy or its alkali metal salt

C₂ -C₅ alkoxycarbonyl

C₂ -C₅ alkylaminocarbonyl

phenylaminocarbonyl

tolylaminocarbonyl

morpholinocarbonyl

amino

nitro

cyano or

dioxolanyl;

pyridinyl;

thienyl provided n is not 2;

furanyl;

furanyl substituted with 1 to 3 of the following groups:

C₁ -C₄ alkyl and

C₂ -C₅ alkoxycarbonyl.

In preferred compounds of the foregoing formula, R¹ is hydrogen or C₁-C₄ linear or branched alkyl and R has one of the following values:

phenyl;

phenyl substituted with 1-2 of the following groups:

F, Cl, Br, except not 2-Cl or 2,4-Cl₂ if n is 2

C₁ -C₄, except p-t-alkyl if n is zero

CF₃

phenyl except if n is 2

C₁ -C₅ alkoxy

C₂ -C₅ alkylcarbonyl

C₂ -C₅ alkoxycarbonyl except 4-alkoxycarbonyl if n is zero

amino

nitro or

cyano;

3- or 4-pyridinyl provided n is not 2

thienyl provided n is not 2;

furanyl;

furanyl substituted with 1 to 3 of the following groups:

methyl or

C₂ -C₃ alkoxycarbonyl.

In more preferred compounds of the above formula, R¹ is hydrogen ormethyl and R has one of the following values:

phenyl provided n is not 2;

phenyl substituted with 1 or 2 of the following groups:

F, Cl, Br, but not 2-Cl or 2,4-Cl₂ if n is 2

n-C₁ -C₄ alkyl

CF₃

C₁ -C₂ alkoxy

C₂ -C₅ alkylcarbonyl, provided n is 1

C₂ -C₃ alkoxycarbonyl provided n is 1 or 2

nitro or

cyano;

3- or 4-pyridinyl provided n is 0 or 1;

thienyl provided n is 0 or 1;

furanyl;

furanyl substituted with 1 to 3 methyl groups, provided n is 1 or 2.

Compounds of the invention may be used for control of various grassesand broadleaved weeds including pigweed (Amaranthus retroflexus L.),velvetleaf (Abutilon theophrasti Medic.), jimsonweed (Datura stramoniumL.), tall morning-glory (Ipomoea purpurea (L.) Roth), barnyardgrass(Echinochloa crusgalli (L.) Beauv.), green foxtail (Setaria viridis (L.)(Beauv.) giant foxtail (Setaria faberi Herrm.), crabgrass (Digitariaischaemum (Schreb.) Muhl.) and switchgrass (Panicum virgatum L.).

Chemical harvest aids are used for a wide variety of primary effects,including the defoliation of the crop plant; the desiccation of itsleaves, stems, and other aerial organs; the control of late-seasonregrowth (e.g. cotton); the concentration of crop maturity providingmore efficient harvesting.

Under normal conditions, many crop plants do not mature uniformly or ina timely fashion, so that efficient, optimum harvest is difficult,either due to equipment scheduling or to weather. Crops such as cotton,potato, sunflower, seed legumes and other oilseed crops require eitherdesiccation or defoliation before harvest can be effectivelyaccomplished. Cotton is an example of a crop with a long history ofsuccessful harvest aid use. When cotton is adequately defoliated,mechanical pickers can operate more effectively. If the crop is notdefoliated, the leaves can interfere with the picking mechanism. Also,leaves can contaminate the cotton lint with trash or green stain, whichreduces the quality of the fiber or reduces the efficiency of theginning process. Likewise, potato vines need to be desiccated forefficient mechanical digging. In addition, upon desiccation of potatoleaves and haulms, the tuber skin matures and becomes less susceptibleto damage from the digger and post-harvest handling. Seed legumes andsunflowers are also mechanically harvested, and this process isfacilitated if the leaves are removed or desiccated. As with cotton andpotato, such defoliation or desiccation also ripens the seed uniformly,accelerates the rate of fruit maturation, and conditions the pod or headfor easy harvest.

Compounds of this invention have been found to have surprising utilityas harvest aid chemicals. Specifically, when applied to the foliage ofcrop species, they cause desiccation and/or defoliation of the leaves,can cause desirable changes in the fruiting form (e.g. cotton boll), andmay alter the re-growth of the plant.

Applications of the compounds may be in the form of aqueous solutions orsuspensions applied to the target tissue. Compounds of this inventionmay be used alone, in combination with one or more other oxathiazinederivative described here, or as a tank mix with other harvest aidchemical compounds or spray adjuvants (such as surface-active agents,stickers, emulsifiers, or extenders).

In addition, the chemicals described for this invention possessantifungal properties which are useful for the control of plant diseasessuch as Rice Blast, Bean Rust, Tomato Early Blight, Cercospora Leaf Spotor similar diseases. Growth inhibition tests indicate a broad spectrumof activity against other disease-producing fungi such as Alternaria,Sclerotium, Piricularia, Pythium, Phytophthora, Fusarium.

Two methods of synthesizing the chemicals of this invention have beendiscovered. One of these is outlined in Scheme I below and utilizesaromatic aldehydes as starting materials. ##STR2##

N-hydroxyarylcarboximidoyl chloride (II) is treated with2-chloroethanethiol in the presence of two equivalents of base orsuitable hydrogen chloride scavenger to produce3-aryl-5,6-dihydro-1,4,2-oxathiazine (I, n=0). The II intermediate maybe readily made by known methods by converting an aldehyde of theformula RCHO to its corresponding oxime (RCH═NOH) in the presence of H₂NOH and subsequent chlorination with chlorine or t-butyl hypochlorite inmethylene chloride or chloroform as the solvent. If only one equivalentof base is used, the intermediate 2-chloroethylN-hydroxybenzene-carboximidothioate derivative is isolated. Thisintermediate will give the oxathiazine when treated with a base.

Oxidation of oxathiazines with peroxyacetic acid orm-chloroperoxybenzoic gives the oxides (I, n=1 or 2).

Scheme II below outlines the second method of preparation, which usesarylcarbodithioate esters. ##STR3##

Treatment of a carbodithioate ester (IV) with hydroxylamine results inthe liberation of ethyl mercaptan and the formation ofN-hydroxyarylthioamide (Va) which enolises toN-hydroxyarylcarboximidothioic acid (Vb). Formation of the oxathiazineis then accomplished by reacting with vicinal dihaloalkane, ##STR4## (R¹and X as previously described) in the presence of two equivalents ofbase. A minor impurity is sometimes obtained in this reaction. Forexample, when two molecules of N-hydroxycarboximidothioic acid (Vb)react with one molecule of 1,2-dibromoethane, 1,2,-ethanediylbis(N-hydroxyarylcarboximidothioate) is produced and can be extractedfrom the reaction by washing with dilute aqueous sodium hydroxide.

In Scheme I, the reaction of compound II with compound III for thepreparation of the desired oxathiazine of this invention may be carriedout at a temperature of minus 10° to plus 20° C. Usually, the reactiontakes about 0.5-6 hours for completion but ordinarily does not takelonger than 3 hours.

In Scheme II, the Step I reaction is performed at from 0° to 30° C.,usually at 10°-25° C., and it may take 0.5-2 hours, generally 0.5-1 hourto form the Va/Vb equilibrium product. In Step 2, a temperature of0°-100° C. may be employed although a 20°-80° C. temperature range ismore preferred. The reaction usually takes from 0.5 to 5 hours, but inmany cases completion can be obtained within 3 hours. As solvents,C_(1-C) ₁₀ aliphatic alcohols may be used or aprotic solvents such asdimethylformamide or dimethylsulfoxide.

If so desired, intermediate compounds suitable for making the chemicalsof this invention may be prepared having the structural formulaRC(═NOH)SCH₂ CH₂ Cl by using Scheme I of this invention wherein R hasthe meanings of claim 1, R¹ is hydrogen and n is 0, using only oneequivalent of base such as alkali metal C₁ -C₁₀ alkoxide, alkylamines,alkanolamines, pyridine, morpholine and similar organic bases.

The preparation of the compounds can best be illustrated by thefollowing specific examples.

Compound numbers are in parenthesis (c.f. Tables 1 to 4).

EXAMPLE 1 2-Chloroethyl 2-chloro-N-hydroxybenzenecarboximidothioate

2-Chlorobenzaldoxime (46.7 g, 0.3 mol) in chloroform (350 ml) was cooledand stirred in an ice/salt bath. Chlorine gas was bubbled into thereaction until an excess was present. Excess chlorine and solvent wereremoved and the remaining 2-chloro-N-hydroxybenzenecarboximidoylchloride dissolved in ether (250 ml). Solutions of triethylamine (30.3g, 0.3 mol) in ether (50 ml) and 2-chloroethanethiol (29 g, 0.3 mol) inether (50 ml) were added simultaneously with stirring and cooling. Afterthe addition, the reaction was allowed to warm to room temperature andleft overnight. Water was added, and the ether layer was washed withadditional water, then dried with anhydrous magnesium sulphate.Evaporation left a white solid, 2-chloroethyl2-chloro-N-hydroxybenzenecarboximidothioate, m.p. 115°-117° C., (Found:C, 43.29; H, 3.58; N, 5.59. C₉ H₉ Cl₂ NOS requires C, 43.21; H, 3.62; N,5.60).

The following compounds of this type were prepared in a similar manner.

    ______________________________________                                         ##STR5##                                                                     V       W       X        Y      Z     m.p. °C.                         ______________________________________                                        H       H       Cl       H      H     110-117                                 Cl      H       Cl       H      H     104-106                                 H       H       CH.sub.3 H      H     118-119                                 CH.sub.3                                                                              H       H        CH.sub.3                                                                             H     86-96                                   ______________________________________                                    

EXAMPLE 2 3-(2-Chlorophenyl)-5,6-dihydro-1,4,2-oxathiazine (3)

2-Chlorethyl 2-chloro-N-hydroxybenzenecarboximidothioate (25 g, 0.1 mol)was added to a cold solution of sodium (2.3 g) in ethanol (150 ml). Anexotherm was observed. The reaction was left at room temperatureovernight, then the ethanol was removed, the product extracted withether, the ether solution washed with water, dried and evaporated toleave an oil. Distillation b.p. 121° C. at 0.02 mm (2.67 pa) gave an oilwhich solidified, 3-(2-chlorophenyl)-5,6-dihydro-1,4,2-oxathiazine, m.p.51°-52° C. (Found: C, 50.30; H, 3.73; N, 6.57. C₉ H₈ ClNOS requires C,50.58; H, 3.77; N, 6.55).

EXAMPLE 3 5,6-Dihydro-3-(4-pyridinyl)-1,4,2-oxathiazine (11)

4-Pyridinecarboxaldehyde oxime (30.6 g, 0.25 mol) was chlorinated inchloroform (350 ml) as described in Example 1 to produceN-hydroxy-4-pyridine-carboximidoyl chloride which was suspended in ether(500 ml) containing 2-chloroethanethiol (26.9 g, 0.25 mol). With icebath cooling, triethylamine (5.1 g, 0.5 mol) was added dropwise. Afterthe addition, water was made, the suspended solid, crude 2-chloroethylN-hydroxy-4-pyridinecarboximidothioate was collected on a filter anddried. This crude ester was added to a solution of sodium ethoxide (from5.75 g sodium in 500 ml ethanol), and the reaction mixture stirred for 4hours. Water was added and the product was extracted with ether to give5,6-dihydro-3-(4-pyridinyl)-1,4,2-oxathiazine, mp 80°-82° C., (found: C,53.16; H, 4.56; N, 15.07. C₈ H₈ N₂ OS requires C, 53.33; H, 4.48; N,15.55).

EXAMPLE 4 5,6-Dihydro-3-[3-trifluoromethyl)phenyl]-1,4,2-oxathiazine(45)

Ethyl 3-(trifluoromethyl)benzenecarbodithioate (24.7 g, 0.1 mol) wasdissolved in ethanol (50 ml) in which was suspended hydroxylaminehydrochloride (7 g, 0.1 mol). With stirring, triethylamine (10.1 g, 0.1mol) in ethanol (25 ml) was added dropwise. After 5 hours, ethylmercaptan was removed under reduced pressure through a KOH scrubber.1,2-Dibromoethane (19 g, 0.1 mol) was added to the reaction mixturefollowed by dropwise addition of triethylamine (30 ml) in ethanol (50ml). A white precipitate formed. After the addition was complete, thereaction mixture was warmed until it was homogeneous, then left at roomtemperature overnight. Water was added, the product extracted intoether, the ether solution washed with dilute sodium hydroxide (2Napprox.), then water, dried over anhydrous magnesium sulphate andevaporated to leave an oil which was distilled to give5,6-dihydro-3-[3-(trifluoromethyl)phenyl]-1,4,2-oxathiazine, bp 113°/0.2mm.

EXAMPLE 5 5,6-Dihydro-3-(2-furanyl)-1,4,2-oxathiazine (31)

Methyl 2-furancarbodithioate (30 g, 0.2 mol) was converted to5,6-dihydro-3-(2-furanyl)-1,4,2-oxathiazine, an oil, bp 128°-129° C. at1.3 mm (173 Pa), preparation similar to Example 4). The sodium hydroxidewash from the ether extract was acidified. An amber oil separated outand on standing, solidified. This solid was collected, washed withether, dried and found to be 1,2-ethandiylbis(N-hydroxy-2-furancarboximidothioate), mp 147°-150° C. (Found: C,45.80; H, 4.08; N, 8.62. C₁₂ H₁₂ N₂ O₄ S₂ requires C, 46.16; H, 3.87; N,8.97.)

EXAMPLE 6 5,6-Dihydro-3-(3-fluorophenyl)-1,4,2-oxathiazine, 4-oxide (28)

5,6-Dihydro-3-(3-fluorophenyl)-1,4,2-oxathiazine (19.7 g, 0.1 mol) wasdissolved in chloroform, 50 ml). 3-Chloroperoxybenzoic acid (21 g)dissolved in chloroform (200 ml) was added dropwise at such a rate thatthe temperature of the reaction mixture remained at between 25° to 30°C. After the addition was complete, the reaction was left stirring atroom temperature overnight. Saturated aqueous sodium bicarbonate wasadded and stirred until all gassing ceased. The chloroform solution waswashed with water, dried over anhydrous magnesium sulphate andevaporated to leave a solid which was recrystallised from ether/ligroin,to give 5,6-dihydro-3-(3-fluorophenyl)-1,4,2-oxathiazine 4-oxide, mp 79°C.

EXAMPLE 7 5,6-Dihydro-3-(3-chlorophenyl)-1,4,2-oxathiazine, 4-oxide (84)

5,6-Dihydro-3-(3-chlorophenyl)-1,4,2-oxathiazine (21.4 g, 0.1 mol) inmethylene chloride (50 ml) was cooled with ice water.3-Chloroperoxybenzoic acid (21 g, 85%) in methylenechloride (150 ml) wasadded dropwise the reaction was stirred and the temperature maintainedin 10° C. After the addition, the reaction was brought to ambienttemperature and stirred overnight. After washing with aqueous sodiumbicarbonate, water and then drying over anhydrous magnesium sulphate,evaporation of the solvent left a solid which was washed with ether anddried to leave 5,6-dihydro-3-(3-chlorophenyl)-1,4,2-oxathiazine,4-oxide, mp 112°-4° C. (Found: C, 47.03; H, 3.43; N, 6.21. C₉ H₈ ClNO₂ Srequires C, 47.07, H, 3.51, N, 6.09.)

EXAMPLE 8 3-(2,6-Dichlorophenyl)-5,6-dihydro-1,4,2-oxathiazine,4,4-dioxide (56)

3-(2,6-Dichlorophenyl)5,6-dihydro-1,4,2-oxathiazine was oxidised as inExample 6 except that two equivalents of 3-chloroperoxybenzoic acid wereused. Thus, 3-(2,6-dichlorophenyl)-5,6-dihydro-1,4,2-oxathiazine4,4-dioxide, mp 180°-182° C. was prepared. (Found: C, 38.40; H, 2.56; N,5.02. C₉ H₇ Cl₂ NO₃ S requires C, 38.58; H, 2.51; N, 5.00.)

EXAMPLE 9 3-(3-Chlorophenyl)-5,6-dihydro-1,4,2-oxathiazine (26)

Ethyl 3-chlorobenzenecarbodithioate (106 g, 0.5 mol) and ethanol (400ml) was treated with finely powdered hydroxylamine hydrochloride (36 g,0.5 mol, 97%) with stirring, triethylamine (50.5 g, 70 ml, 0.5 mol) wasadded dropwise. A slight exotherm was observed. After the addition, thereaction was stirred for 11/2 hours. Ethyl mercaptan was removed using ascrubber and vacuum trap. 1,2-Dibromoethane (95 g, 0.5 mol) was added tothe reaction and with stirring, triethylamine (101 g, 140 ml, 1 mol)added dropwise. The initial red colour was completely discharged. Whenthe addition was complete, the reaction was refluxed for 1 hour, cooledto room temperature and the solvent removed to leave a solid. Water wasadded, the product extracted into ether which was subsequently washedsuccessively with water, 5% potassium hydroxide, water and then driedover anhydrous magnesium sulphate. After evaporation, a white solidremained, 3-(3-chlorophenyl)-5,6-dihydro-1,4,2-oxathiazine, mp 65° C.

EXAMPLE 10 3-(3-Fluorophenyl)-5,6-dihydro-1,4,2-oxathiazine (27)

2-Chloroethyl 3-fluoro-N-hydroxybenzenecarboximidothioate was made in amanner similar to that described in Example 1 using the followingmaterials:

3-Fluorobenzaldehyde oxime (27.8 g, 0.2 mol)

2-Chloroethanethiol (21.5 g, 0.2 mol)

Triethylamine (40.8 g, 0.4 mol)

Ether (400 ml)

Cyclisation of 2-chloroethyl 3-fluoro-N-hydroxybenzenecarboximidothioatewas accomplished as described in Example 2 using sodium (4.6 g) inethanol (300 ml) to give3-(3-fluorophenyl)-5,6-dihydro-1,4,2-oxathiazine, mp 47°-9° C. (Found:C,54.66; H,4.13; N,7.07. C₉ H₈ FNOS requires C,54.81; H,4.09; N,7.10).

EXAMPLE 11 5,6-Dihydro-3-(3-nitrophenyl)-1,4,2-oxathiazine (12)

5,6-Dihydro-3-(3-nitrophenyl)-1,4,2-oxathiazine, mp 114°-5° C., wasprepared in a manner as described in Example 9 using the followingmaterials:

Methyl 3-nitrobenzenecarbodithioate, (117 g, 0.55 mol)

Ethanol (250 ml)

Hydroxylamine hydrochloride (40 g, 0.55 mol)

1,2-Dibromoethane (40 ml)

Triethylamine (80 ml) and a further (160 ml).

EXAMPLE 12 3-(4-Chlorophenyl)-5,6-dihydro-1,4,2-oxathiazine (1)

2-Chloroethyl 4-chloro-N-hydroxybenzenecarboximidothioate (2.5 g, 0.01mol) was cyclised with sodium (0.23 g) in ethanol (25 ml) as describedin Example 2. 3-(4-Chlorophenyl)-5,6-dihydro-1,4,2-oxathiazine, mp80.5°-81.5° C., was isolated. (Found: C,50.16; H,4.24; N,6.44. C₉ H₈ClNOS requires C,50.58; H,3.77; N,6.55.)

EXAMPLE 13 (3-(4-bromophenyl)-5,6-dihydro-1,4,2-oxathiazine (70)

3-(4-Bromophenyl)-5,6-dihydro-1,4,2-oxathiazine, mp 114°-5° C., was madeas described in Example 9 using the following materials:

Ethyl 4-bromobenzenecarbodithioate (130.5 g, 0.5 mol)

Ethanol (500 ml)

Hydroxylamine hydrochloride (97%) (36 g, 0.5 mol)

1,2-dibromoethane (45 ml)

Triethylamine (72 ml) and a further (140 ml).

EXAMPLE 14 3-(3,5-dichlorophenyl)-5,6-dihydro-1,4,2-oxathiazine (64)

3-(3,5-Dichlorobenzenecarbodithioate (50 g, 0.2 mol), mp 88°-9° C.

Ethanol 250 ml

Hydroxylamine hydrochloride 14.5 g, 0.2 mol

Triethylamine (28 ml) in ethanol (30 ml)

1,2-dibromoethane (25 ml)

Triethylamine (56 ml)

EXAMPLE 15 5,6-Dihydro-3-(2-thienyl)-1,4,2-oxathiazine (37)

5,6-Dihydro-3-(2-thienyl)-1,4,2-oxathiazine, mp 86°-89° C., was made asdescribed in Example 9 using the following materials:

Methyl 2-thiophenecarbodithioate (35 g, 0.2 mol)

Ethanol (100 ml)

Hydroxylamine hydrochloride (14 g, 0.2 mol)

1,2-Dibromoethane (37.6 g, 0.2 mol)

Triethylamine (28 ml) and a further (56 ml)

EXAMPLE 16 Ethyl 4-(5,6-dihydro-1,4,2-oxathiazine-3-yl)benzoate (80)

Ethyl 4-(5,6-dihydro-1,4,2-oxathiazine-3-yl)benzoate, mp 69°-70° C. wasprepared as outlined in Example 9 using the following:

Ethyl 4-[(methylthio)thioxomethyl]benzoate (83 g, 0.35 mol)

Ethanol (200 ml)

Hydroxylamine hydrochloride (97%) (25 g, 0.35 mol)

Triethylamine (50 ml) in ethanol (50 ml)

1,2-Dibromoethane (30 ml)

Triethylamine (100 ml).

EXAMPLE 17 3-(3-Chlorophenyl)-5,6-dihydro-5-(or6)-methyl-1,4,2-oxathiazine (92)

3-(3-Chlorophenyl)-5,6-dihydro-5-(or 6)-methyl-1,4,2-oxathiazine, bp145° C. at 0.25 mm (33.3 Pa), was prepared as described in Example 9using the following:

Ethyl 3-chlorobenzenecarbodithioate (43.2 g, 0.2 mol)

Ethanol 200 (ml)

Hydroxylamine hydrochloride (14.5 g, 0.2 mol)

1,2-Dibromopropane (40.5 g, 0.2 mol)

Triethylamine (28 ml) and a further (56 ml).

EXAMPLE 18 [(3-(5,6-Dihydro-1,4,2-oxathiazine-3-yl)]-N-phenylbenzamide(100)

3-(5,6-Dihydro-1,4,2-oxathiazine-3-yl)benzoic acid (15 g, 0.07 mol) wassuspended in methylene chloride (200 ml). Thionyl chloride (10 ml) wasadded and the reaction was refluxed until homogenous and all gassing hadceased. The solvent was removed, the remaining oil was taken up inmethylene chloride and treated portionwise with aniline (12.5 g, 0.12mol). An exotherm was observed. After several hours, water was added,the organic material separated, washed successively with water, aqueousbicarbonate, dilute hydrochloric acid, water and then dried overanhydrous magnesium sulphate. Evaporation of the solvent left a solidwhich was recrystallised from ethanol to give crystals of3-(5,6-dihydro-1,4,2-oxathiazin-3-yl)-N-phenylbenzamide, mp 149°-150° C.(Found: C,64.65; H,4.92; N,9.65. C₁₆ H₁₄ N₂ O₂ S requires C,64.42;H,4.73; N,9.39).

                                      TABLE 1                                     __________________________________________________________________________     ##STR6##                                                                     COM-                                                                          POUND                                                                              V  W      X        Y  Z m.p. °C. or bp.                           __________________________________________________________________________    1    H  H      Cl       H  H 80.5-81.5                                        3    Cl H      H        H  H 51-52, 121 at 0.02 mm (2.67 Pa)                  6    Cl H      Cl       H  H 137-141° at 0.05 mm (6.67 Pa)             8    H  H      CH.sub.3 H  H 125-128° at 1.5 mm (200 Pa)               9    CH.sub.3                                                                         H      H        CH.sub.3                                                                         H 139-140° at 0.4 mm (53.3 Pa)              12   H  NO.sub.2                                                                             H        H  H 114-115                                          13   H  Cl     Cl       H  H 77-78                                            16   CH.sub.3                                                                         H      H        H  H 160 at 3 mm (400 Pa)                             18   H  H      H        H  H 47-49                                            26   H  Cl     H        H  H 65                                               27   H  F      H        H  H 47-49                                            30   H  CH.sub. 3                                                                            H        H  H 52-54                                            34   H  H      OCH.sub.3                                                                              H  H 91-92                                            35   H  OCH.sub.3                                                                            H        H  H oil                                              39   H  H      F        H  H 46-48; 90° at 0.05 mm (6.67 Pa)           47   Cl H      H        H  F oil                                              48   H  H      CN       H  H 115-118                                          51   H  H      COCH.sub.3                                                                             H  H 128-129                                          54   Cl H      H        H  Cl                                                                              96-97                                            60   H  H      OC.sub.6 H.sub.5                                                                       H  H 98-100                                           62   H  H      COC.sub.6 H.sub.5                                                                      H  H 125-126                                          63   H  H      O(CH.sub.2).sub.3 CH.sub.3                                                             H  H 96-7                                             64   H  Cl     H        Cl H 88-9                                             69   H  H      C(CH.sub.3).sub.3                                                                      H  H 86-90                                            70   H  H      Br       H  H 114-5                                            71   H  H      (CH.sub.2).sub.3 CH.sub.3                                                              H  Oil                                                78   H  H      CF.sub.3 H  H 110-1                                            80   H  H      CO.sub.2 CH.sub.2 CH.sub.3                                                             H  H 69-70                                            79   H  H      CO.sub.2 H                                                                             H  H 225                                              87   H  CO.sub.2 CH.sub.3                                                                    H        H  H 65-6                                             45   H  CF.sub.3                                                                             H        H  H 113° at 0.2 mm (26.7 Pa)                  88   H  H      C.sub.6 H.sub.5                                                                        H  H 147-150                                          89   H  Br     H        H  H 95-97                                            93   H  CO.sub.2 H                                                                           H        H  H 168-171                                          98   H  H      SCH.sub.3                                                                              H  H 104-105                                          99   H  H      CONHC.sub.6 H.sub.4                                                                    H  H 183-185                                                         2-CH.sub.3                                                     100  H  CONHC.sub.6 H.sub.5                                                                  H        H  H 149-150                                          101  H  H      SOCH.sub.3                                                                             H  H 116-117                                          107  H  H      O2-Tetra-                                                                              H  H 93-94                                                           hydropyranyl                                                   108  H  H      OCH.sub.2 CH.sub.3                                                                     H  H 95-96                                            109  H  H      OC.sub.5 H.sub.11                                                                      H  H 93-95                                            92.sup.(2)                                                                         H  Cl     H        H  H 145/0.25 mm                                      110  H  H      CO4-Mor- H  H 125-126                                                         pholinyl                                                       111  H  CH.sub.3                                                                             NO.sub.2 H  H 116-117                                          115  H  NH.sub.2                                                                             H        H  H 71-74                                            116  H  CO.sub.2 CH.sub.2 CH.sub.3                                                           H        H  H 47-49                                            117  H  H      CO.sub.2 CH.sub.3                                                                      H  H 142-143                                          118  H  H      CO.sub.2 K                                                                             H  H >250                                             119  H  H      OH       H  H 160-161                                          125  H  COOK   H        H  H >250                                             126.sup.(1)                                                                        H  Cl     H        H  H 51-54.5                                          127  H  H      NO.sub.2 H  H 168-170                                          130  H  CN     H        H  H 70-72                                            132  F  H      H        H  H 125/0.25 mm                                      139.sup.(2)                                                                        Cl H      H        H  H oil                                              140.sup.(3)                                                                        H  Cl     H        H  H oil                                              __________________________________________________________________________     .sup.(1) Methyl group on 6 position of the 1,4,2oxathiazine ring.             .sup.(2) Methyl group on 5 or 6 position of the 1,4,2oxathiazine ring.        .sup.(3) Methyl group on 5 position of the 1,4,2oxathiazine ring.        

                  TABLE 2                                                         ______________________________________                                         ##STR7##                                                                     COM-                                                                          POUND  V     W          X         Y   Z   m.p. ° C.                    ______________________________________                                        5      H     H          Cl        H   H   72-75                               15     H     NO.sub.2   H         H   H   149-153                             19     H     Cl         Cl        H   H   104-7                               28     H     F          H         H   H   78-81                               29     H     H          H         H   H   68-70                               32     H     CH.sub.3   H         H   H   68-69                               36     H     H          OCH.sub.3 H   H   109-112                             41     H     OCH.sub.3  H         H   H   62-64                               42     H     H          CH.sub.3  H   H   100-102                             46     H     CF.sub.3   H         H   H   89-90                               52     H     H          COCH.sub.3                                                                              H   H   159-160                             55     Cl    H          H         H   Cl  133-135                             61     H     H          OC.sub.6 H.sub.5                                                                        H   H   155-157                             67     H     H          O(CH.sub.2).sub.3 CH.sub.3                                                              H   H   77-8                                68     H     Cl         H         Cl  H   135-6                               73     H     H          (CH.sub.2).sub.3 CH.sub.3                                                               H   H   68                                  75     H     H          C(CH.sub.3).sub.3                                                                       H   H   101-3                               76     H     H          Br        H   H   113-5                               82     H     H          CO.sub.2 CH.sub.2 CH.sub.3                                                              H   H   106-8                               84     H     Cl         H         H   H   112-4                               86     H     H          CF.sub.3  H   H   142-5                               91     H     CO.sub.2 CH.sub.3                                                                        H         H   H   103-104                             95     H     H          C.sub.6 H.sub.5                                                                         H   H   138-144                             96     H     Br         H         H   H   104-106                             102    H     CONHC.sub.6 H.sub.5                                                                      H         H   H   158-160                             103    H     H          SOCH.sub.3                                                                              H   H   140-142                             104    H     H          SO.sub.2 CH.sub.3                                                                       H   H   160-163                             112    H     H          CONHC.sub.6 H.sub.4                                                                     H   H   168-169                                                     2-OCH.sub.3                                           113    H     H          OC.sub.5 H.sub.11                                                                       H   H   68-70                               120    H     CH.sub.3   NO.sub.2  H   H   156-158                             121    H     H          COmor-    H   H   182-183                                                     pholinyl                                              122    H     H          OCH.sub.2 CH.sub.3                                                                      H   H   125-127                             133    H     CN         H         H   H   153-155                             134    H     H          COOCH.sub.3                                                                             H   H   137-138                             135.sup.(1)                                                                          H     Cl         H         H   H   95-99.5                             136    H     H          NO.sub.2  H   H   190-193                             140    Cl    H          H         H   H   94-95                               141    F     H          H         H   H   102-104                             ______________________________________                                         .sup.(1) Methyl group on 6 position of the 1,4,2oxathiazine ring.        

                                      TABLE 3                                     __________________________________________________________________________     ##STR8##                                                                     COMPOUND                                                                              V  W      X       Y  Z m.p. °C.                                __________________________________________________________________________    4       Cl H      H       H  H 125-127                                        7       Cl H      Cl      H  H 101.5-102                                      17      H  NO.sub.2                                                                             H       H  H 135-140                                        20      CH.sub.3                                                                         H      H       H  H 118-120                                        25      CH.sub.3                                                                         H      H       CH.sub.3                                                                         H 85-86                                          43      H  H      CH.sub.3                                                                              H  H 131.5-132.5                                    49      H  H      CN      H  H 115-118                                        53      H  H      COCH.sub.3                                                                            H  H 142-144                                        56      Cl H      H       H  Cl                                                                              180-182                                        57      H  H      H       H  H 98-99                                          58      H  Cl     Cl      H  H 145-147                                        59      H  H      Cl      H  H 89-90                                          65      H  Cl     H       Cl H 133-4                                          66      H  H      O(CH.sub.2).sub.3 CH.sub.3                                                            H  H 104-5                                          72      H  H      (CH.sub.2).sub.3 CH.sub.3                                                             H  H 88-90                                          74      H  H      C(CH.sub.3).sub.3                                                                     H  H 133-4                                          77      H  H      Br      H  H 147-8                                          81      H  H      CO.sub.2 CH.sub.2 CH.sub.3                                                            H  H 118-20                                         83      H  Cl     H       H  H 102-4                                          85      H  H      CF.sub.3                                                                              H  H 158-9                                          90      H  CO.sub.2 CH.sub.3                                                                    H       H  H 101-102                                        94      H  H      C.sub.6 H.sub.5                                                                       H  H 142-145                                        97      H  Br     H       H  H 99-102                                         105     H  H      CONHC.sub.6 H.sub.4                                                                   H  H 212-213                                                          2-CH.sub.3                                                  106     H  CONHC.sub.6 H.sub.5                                                                  H       H  H 162-163                                        114     H  H      OC.sub.5 H.sub.11                                                                     H  H 66-67                                          123     H  H      COmorpho-                                                                             H  H 165-168                                                          linyl                                                       124     H  H      OCH.sub.2 CH.sub.2                                                                    H  H 123-124                                        128     H  CH.sub.3                                                                             NO.sub.2                                                                              H  H 140-141                                        129     H  CF.sub.3                                                                             H       H  H 104-104.5                                      137     H  H      COOCH.sub.3                                                                           H  H 173-176                                        138.sup.(1)                                                                           H  Cl     H       H  H 123-126                                        142     H  CN     H       H  H 155-159                                        143     F  H      H       H  H 130-132                                        __________________________________________________________________________     .sup.(1) Methyl group on 6 position of the 1,4,2oxathiazine ring.        

                  TABLE 4                                                         ______________________________________                                         ##STR9##                                                                     COM-                                                                          POUND  R           n     m.p. °C./bp.                                  ______________________________________                                        14     2-pyridinyl 0     135-137                                              23     2-pyridinyl 1     180                                                  10     3-pyridinyl 0     125-128 at 0.05 mm (6.67 Pa)                         24     3-pyridinyl 1     46-51                                                21     4-pyridinyl 1     150-158                                              22     4-pyridinyl 2     185                                                  33     2-furanyl   1     77-78                                                44     2-furanyl   2     92-93                                                37     2-thienyl   0     86-89                                                38     2-thienyl   1     107-109                                              40     2,4,5-trimethyl-                                                                          0     mp 35; bp 132/0.1 mm (13.3 Pa)                              3-furanyl                                                              11     4-pyridinyl 0     80-82                                                31     2-furanyl   0     128-129/1.3 mm                                       131    4-ethyoxycar-                                                                             0     66-7                                                        bonyl-3,5-                                                                    dimethyl-2-                                                                   furanyl                                                                ______________________________________                                    

All of the above compounds in Tables 1 to 4 were confirmed by elementalanalysis and/or N.M.R. spectra and/or infrared spectra.

Compounds within the contemplation of this invention include thefollowing (n being 0, 1 or 2):

    ______________________________________                                        V      W     X              Y   Z      n                                      ______________________________________                                        H      H     CONHC.sub.4 H.sub.9                                                                          H   H      0 or 1                                 H      H     CONHCH.sub.3   H   H      0 or 1                                 H      H     CN             H   H      1                                      H       Cl   Cl             H   H      1                                      H       Cl   H              H   H      .sup. 1.sup.1                          ______________________________________                                         .sup.1 Methyl group on 5 position of the 1,4,2oxathiazine ring.          

As indicated above, compounds of the invention are particularly usefulin herbicidal, fungicidal, defoliant and desiccant applications,particularly in the form of an agricultural chemical formulationcomprising an effective amount of the compound in admixture with acarrier therefor.

For herbidical (post-emergent or pre-emergent) applications, a preferredclass of compounds are those of the general formula given above, inwhich R¹ is hydrogen, C₁ -C₄ linear or branched alkyl or bnezyl, n is 0,1 or 2 and R has one of the following values:

phenyl or naphthyl;

phenyl substituted with 1 or 2 of the following groups:

halogen except 2-Cl if n is 2

C₁ -C₁₂ alkyl

C₅ -C₆ cycloalkyl

trihalomethyl

C₁ -C₈ alkoxy (but not C₄ -C₈ alkoxy if n is zero or 2)

phenoxy

tetrahydropyranyloxy

C₁ -C₈ alkylthio

C₁ -C₄ alkylsulfinyl

C₁ -C₄ alkylsulfonyl

C₂ -C₅ alkylcarbonyl provided n is 0 or 1

carboxyl or its alkali metal salt

2- or 3-(C₂ -C₅ alkoxycarbonyl)

4-(C₂ --C₅ alkoxycarbonyl) provided n is 0 or 1

C₂ -C₅ alkylaminocarbonyl

morpholinocarbonyl

amino

nitro

cyano

dioxolanyl;

4-pyridinyl if n is zero or 1;

thienyl provided n is not 2;

furanyl;

furanyl substituted with 1 to 3 of the following groups:

C₁ -C₄ alkyl

C₂ -C₅ alkoxycarbonyl.

More preferred herbicidal compounds are those wherein:

R¹ is hydrogen or C₁ -C₄ linear or branched alkyl and

if n is zero, 1 or 2,

R=phenyl substituted with 1 or 2 of the following groups:

3-CF₃

n-C₁ -C₄ alkyl provided they are in 3- or 4-position;

3-pyridinyl;

furanyl;

furanyl substituted with 1 to 3 of the following groups:

methyl

C₂ -C₃ alkoxycarbonyl.

if n is zero or 1,

R=phenyl;

phenyl substituted with 1 or 2 of the following groups:

F or Cl

trifluoromethyl;

thienyl;

if n is 1,

R=phenyl substituted with 1 or 2 of the following groups:

4-Br

4-CF₃

C₁ -C₅ alkoxy

3-nitro

3-cyano.

Still more preferred herbicidal compounds are those wherein:

R¹ is hydrogen or methyl, and

if n is zero, 1 or 2,

R=phenyl substituted with 1 or 2 of the following groups:

4-Cl

3- or 4-(n-C₁ -C₃ alkyl);

if n is 1 or 2,

R=2-furanyl;

if n is 1,

R=phenyl;

phenyl substituted with 1 or 2 of the following groups:

3-Cl or 3-F

4-trifluoromethyl

3-methoxy

3-nitro

4-(C₁ -C₄ alkyl);

2-thienyl;

if n is zero or 1,

R=3-pyridinyl;

if n is zero,

R=phenyl substituted with one of the following groups:

2,4-Cl₂

2-Cl

3-Cl

4-F

2-Cl-6-F.

For fungicidal applications, a preferred class of compounds are those ofthe formula given above, in which R¹ is hydrogen, C₁ -C₄ linear orbranched alkyl or benzyl, n is 0, 1 or 2, and R has one of the followingvalues:

phenyl or naphthyl;

phenyl substituted with 1-2 of the following groups:

hydroxyl

halo

C₁ -C₁₂ alkyl

C₅ -C₆ cycloalkyl

trihalomethyl

phenyl

C₁ -C₅ alkoxy or alkylthio

C_(2-C) ₅ alkylcarbonyl

phenylcarbonyl

C₁ -C₄ alkylsulfinyl

C₁ -C₄ alkylsulfonyl

carboxy or its alkali metal salt

C₂ -C₅ alkoxycarbonyl

C₂ -C₅ alkylaminocarbonyl

phenylaminocarbonyl

tolylaminocarbonyl

morpholinocarbonyl, except when n is zero

amino

nitro

cyano

dioxolanyl;

pyridinyl, except 4-pyridinyl if n is zero;

thienyl provided n is not 2;

furanyl;

furanyl substituted with 1 to 3 of the following groups:

C₁ -C₄ alkyl

C₂ -C₅ alkoxycarbonyl.

More preferred fungicidal compounds are those wherein:

R¹ is hydrogen or C₁ -C₄ linear or branched alkyl, and

if n is zero, 1 or 2,

R=phenyl or naphthyl;

phenyl substituted with 1 or 2 of the following groups:

F, Cl or Br in 3- or 4-positions;

if n is 1 or 2,

R=phenyl substituted with 1 or 2 of the following groups:

3- or 4-(C₁ -C₄ alkyl)

3- or 4-trifluoromethyl

C₁ -C₄ alkoxy

phenoxy

C₂ -C₅ alkylcarbonyl

C₂ -C₃ alkoxycarbonyl

nitro

cyano;

if n is 1,

R=biphenylyl;

3-cyanophenyl;

4-pyridinyl;

thienyl.

Still more preferred fungicidal compounds are those in which,

R¹ is hydrogen or methyl;

n is 1 or 2;

R is phenyl;

phenyl substituted with 1-2 of the following groups:

F or Cl

methyl

3-trifluoromethyl

3-methoxy

methylcarbonyl

3-methoxycarbonyl

4-methoxycarbonyl provided n is 1

4-ethoxycarbonyl

nitro;

2-thienyl if n is 1;

2-furanyl.

For desiccating plants, a preferred class of compounds are those inwhich R¹ is hydrogen, C₁ -C₄ linear or branched alkyl or benzyl and

if n is zero, 1 or 2,

R=phenyl or naphthyl;

phenyl substituted with 1-2 of the following groups:

Cl or Br in the 3-position

C₁ -C₁₂ alkyl in the 3- or 4 position

3-trihalomethyl

C₁ -C₃ alkoxy or alkylthio

C₁ -C₄ alkylsulfinyl

C₁ -C₄ alkylsulfonyl

carboxy or its alkali metal salt

3-methoxycarbonyl

4-ethoxycarbonyl

amino

cyano

dioxolanyl;

3-pyridinyl;

4-nitrotolyl;

furanyl;

furanyl substituted with 1-3 of the following groups:

C₁ -C₄ alkyl

C₂ -C₅ alkoxycarbonyl;

if n is 1 or 2,

R=phenyl substituted with:

2-F or 4-Br

4-trihalophenyl

3-ethoxycarbonyl

4-methoxycarbonyl

4-nitro;

if n is zero or 1,

R=phenyl substituted with

2-Cl

2-methyl

2,5-(CH₃)₂

C₂ -C₅ alkylcarbonyl

morpholinocarbonyl;

4-pyridinyl;

thienyl;

if n is zero,

R=phenyl substituted with

3-F

2,6-Cl₂ or 2-Cl-6-F;

R=2-pyridinyl.

More preferred compounds for desiccating plants are those in which R¹ ishydrogen or C₁ -C₄ linear or branched alkyl and

if n is zero, 1 or 2,

R=phenyl;

phenyl substituted with

3-(Cl or Br)

3,4-Cl₂

3-methoxy

3-CF₃ ;

3-pyridinyl;

furanyl;

if n is zero or 1,

R=phenyl substituted with:

2-(Cl or F)

3- or 4-(n-C₁ -C₄ alkyl)

2,5-(CH₃)₂

3-trifluoromethyl

3-methoxycarbonyl;

4-pyridinyl;

thienyl;

if n is zero,

R=phenyl substituted with 2-methyl;

if n is 1 or 2,

R=phenyl substituted with 4-CF₃ ;

if n is 1,

R=3-nitrophenyl.

For defoliating plants a preferred class of compounds are those in whichR¹ is hydrogen, C₁ -C₄ linear or branched alkyl or benzyl and

if n is zero, 1 or 2,

R=phenyl;

phenyl substituted with 1-2 groups:

3- or 4-halo

3,5-Cl₂

2-(C₁ -C₄ alkyl)

4-(C₃ -C₄ alkyl)

2,5-(CH₃)

phenyl

3-methoxy

4-(C₂ -C₄ alkoxy)

C₂ -C₅ alkylcarbonyl

3- or 4-carboxy, alkali metal salt

4-methoxycarbonyl

C₂ -C₅ alkylaminocarbonyl

phenylaminocarbonyl

amino

3-nitro

3-cyano;

3- or 4-pyridinyl;

furanyl;

n is zero or 1,

R=phenyl substituted with:

2-halo

2,4-dihalo

2,5-(CH₃)₂

4-CF₃

4-pentyloxy

3-(C₂ -C₃ alkoxycarbonyl)

morpholinocarbonyl;

thienyl;

n is 1 or 2,

R=phenyl substituted with:

3-CF₃

4-methoxy

4-nitro

4-nitrotolyl

3,4-Cl₂ ;

n is zero,

R=phenyl

phenyl substituted with:

2-halo

3-methyl

3,5-(CH₃)₂

phenoxy;

furanyl substituted with methyl and ethoxycarbonyl;

n is 1,

R=phenyl substituted with:

2,6-Cl₂

4-CH₃

4-ethoxycarbonyl;

n is zero or 2,

phenyl substituted with tolylaminocarbonyl or 2-methyl.

More preferred compounds for defoliating plants are those in which R¹ ishydrogen or C₁ -C₄ linear or branched alkyl and

if n is zero, 1 or 2,

R=phenyl substituted with:

3-halo

3,5-Cl₂

3-methoxy

4-carboxy alkali metal salt

3-amino

3-nitro

3-cyano;

3- or 4-pyridinyl;

is n is zero or 1,

R=phenyl substituted with:

2-halo

4-(Br or Cl

2,4-Cl₂

2,5-(CH₃)₂ ;

2-thienyl;

if n is zero, 1 or 2,

R=phenyl substituted with:

3-CF₃

3-CH₃ -4-NO₂

4-nitro

4-methoxy;

if n is 0,

R=phenyl substituted with:

phenoxy;

if n is 1,

R=phenyl substituted with

4-(C₁ -C₄ n-alkyl)

C₂ -C₄ alkoxy

4-methylcarbonyl

3-(C₂ -C₃ alkoxycarbonyl)

4-methoxycarbonyl.

For herbicidal applications, compounds of this invention may be added asa "tank mix" to other herbicide solutions so that the number ofdifferent weed species controlled in a single application will beincreased.

The procedures for using the present oxathiazine derivatives asherbicides may be in accordance with conventional agricultural practice.The chemicals are ordinarily applied as formulations containing acarrier and/or surface-active agent. The formulation may contain morethan one of the described oxathiazine derivatives if desired; otheractive herbicides may be included in the formulation as well.

Thus, the chemical may be impregnated on finely divided or granularinorganic or organic carriers such as attapulgite clay, sand,vermiculite, ground corn cobs, activated carbon or other granularcarriers known to the art. The impregnated granules may then be spreadon the soil as preemergence herbicides. Furthermore, the chemical may beformulated as wettable powders by grinding them into a fine powder andmixing them with an inactive powdered carrier to which a surface activedispersing agent has been added. Typical powdered solid carriers are thevarious mineral silicates, e.g., mica, talc, pyrophyllite and clays. Thewettable powder may then be dispersed in water and sprayed on the soilsurface or weeds. Similarly, soluble or emulsifiable concentrate may beprepared by first dissolving the chemical in a solvent. The choice ofsolvent depends on the solubility of the particular chemical. Commonlyused solvents are acetone, methyl ethyl ketone, C₁ -C₈ alcohols such asmethanol, ethanol, butanol, hexanol and 2-ethylhexanol; toluene, xylene,chloroform, furfuryl alcohol, phenol, naphtha, petroleum ether, keroseneor other aliphatic cycloaliphatic or aromatic solvents. usually, asurface active agent or dispersant is added to the solvent. Theresultant concentrate is then dispersed in water and applied byspraying. Suitable surface active agents and dispersants are well knownto those skilled in the art and reference may be had to McCutcheon'sDetergents and Emulsifiers, 1980, Allured Publishing Corp., Ridgewood,N.J.; or Hoffman et al. U.S. Pat. Nos. 2,614,916, cols, 2 to 4 and2,547,724, cols, 3 and 4, for example of appropriate surface activeagents. The concentration of active chemical in the formulation may varywidely, e.g., from 1 to 95%. For use as a preemergence herbicide, thechemical is applied to soil which contains weed and crop seed (either tothe surface of the soil or incorporated into the upper 2.5 to 7.6 cm ofsoil).

The most suitable rate of application in any given case will depend onsuch factors as soil type, soil pH, soil organic matter content, thequantity and intensity of rainfall before and after treatment, the airand soil temperature, light intensity and light duration per day. All ofthese factors have an influence on the efficacy of the chemicals for useas herbicides.

EXAMPLE 18

To illustrate herbicide efficacy of the described3-aryl-5,6-dihydro-1,4,2-oxathiazines, 600 mg chemical was dissolved in10 ml organic solvent to which 30 mg conventional emulsifying agent(e.g., ethoxylated sorbitan monolaurate "Tween 20" [trademark]) wasadded; in most cases acetone was used as the solvent. The solution wasdiluted to 100 ml with distilled water. Twenty milliliters of this 6000ppm solution was diluted to 250 ppm with distilled water. The chemicalwas applied at the rate of 11.2 kg/ha (kilograms per hectare) bydrenching 46 ml of the 250 ppm solution on the surface of soil in 11.4cm diameter plastic pots which had been sown with the following weedseeds: velvetleaf (Abutilon theophrasti Medic.) or rough pigweed(Amaranthus retroflexus L.), jimsonweed (Datura stramonium L.), tallmorningglory (Ipomea purpurea (L.) Roth), crabgrass (Digitaria ischaemum(Schreb.) Muhl) or switchgrass (Panicum virgatum L.), barnyardgrass(Echinochloa crusgalli (L.) Beauv.) and giant foxtail (Setaria faberiHerrm.) or green foxtail (Setaria viridis (L.) Beauv.). The percentcontrol of the weeds compared to untreated checks was determined twoweeks after treatment. TABLE 5 shows the results with the preemergenceherbicides of the invention prepared in accordance with the aboveexamples.

EXAMPLE 19

To illustrate effectiveness of the described oxathiazines aspostemergence herbicides, the 6000 ppm solutions described under Example18 were atomized with a number 152 DeVilbiss (trademark) sprayer,wetting the foliage to the drip point. The weeds, which are the samespecies as described under Example 18, were treated six days afteremergence. The percent control was evaluated two weeks after treatment.TABLE 6 shows the results with postemergence herbicides of theinvention.

                                      TABLE 5                                     __________________________________________________________________________    PREEMERGENCE HERBICIDE ACTIVITIES OF OXATHIAZINES AT 11.2 kg/ha                       PERCENT WEED CONTROL                                                          PIGWEED                      CRABGRASS                                                                             GIANT OR                                 OR       JIMSON                                                                             MORNING                                                                              BARNYARD                                                                              OR SWITCH-                                                                            GREEN***                         COMPOUND                                                                              VELVETLEAF*                                                                            WEED GLORY  GRASS   GRASS** FOXTAIL                          __________________________________________________________________________    5        98      0    0      10       0      25                               9        90      0    0      25       0      0                                10       90      75   0      50      25      0                                13      100      0    10     15       0      0                                18      100      0    0      0        0      0                                27       85      0    0      0        0      0                                28      100      0    35     30      95      98***                            29      100      0    0      30      95      95***                            30      100      0    0      20      80      80***                            32      100      0    0      50      25       0***                            33       95      98   0      50       0      25***                            36      100      0    0      15       0       0***                            37      100      0    0      0        0       0***                            38      100      0    0      35      30      30***                            39      100      0    100    0        0       0***                            41      100      0    0      0       75       0***                            42      100      0    0      50      75      75***                            43       40      0    0      0        0       0***                            44       70      0    0      30      80      65***                            46      100      0    0      0        0       0***                            47      --       95   0      0       100     100***                           54      --       0    0      80      90**    100***                           55      --       100  0      90      95**    75***                            56      --       100  0      50      80**    25***                            67       0*      0    0      40      20**    80***                            68       0*      0    0      25      50**    95***                            73       0*      0    0      50      95**    50***                            75       0*      0    0      60      95**    95***                            76       0*      0    0      50      90**    95***                            78       0*      0    0      0       30**    50***                            84       0*      70   0      30      50**     0***                            86       0*      75   0      75      95**    95***                            122      0*      0    0      50      15**    60***                            129     100*     0    0      0        0**    90***                            133      0       0    0      50      30**    50***                            135      0*      0    0      75      90**    80***                            __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________    POSTEMERGENCE HERBICIDE ACTIVITY OF OXATHIAZINES AT 6000 PPM                          PERCENT WEED CONTROL                                                          PIGWEED                      CRABGRASS                                                                             GIANT OR                                 OR       JIMSON                                                                             MORNING                                                                              BARNYARD                                                                              OR SWITCH-                                                                            GREEN***                         COMPOUND                                                                              VELVETLEAF*                                                                            WEED GLORY  GRASS   GRASS** FOXTAIL                          __________________________________________________________________________    1       100      90   5      95      100     100                              3       100      35   65     100     85      100                              5       100      100  100    100     100     100                              6       100      100  30     100     100     100                              7       0        0    5      10      5       5                                8       100      100  90     100     100     100                              9       100      10   98     100     100     100                              10      100      0    20     95      95      95                               11      100      5    35     35      50      75                               12      50       0    10     25      10      0                                13      100      0    10     15      0       0                                15      100      50   98     95      80      30                               16      20       5    10     20      25      15                               17      25       5    10     10      5       5                                18      100      20   45     90      75      50                               19      65       10   35     60      20      10                               20      0        0    0      10      0       0                                21      100      5    25     60      95      50                               24      100      100  100    95      75      45                               25      5        5    5      25      10      10                               26      100      100  70     98      98      95                               27      100      5    15     98      100     98                               28      100      100  100    100     100     100***                           29      100      100  100    100     100     100***                           30      100      5    50     100     100     100***                           31      100      10   30     95      100     100***                           32      100      100  100    100     100     100***                           33      100      100  100    95      100     100***                           34      100      0    5      90      75      90***                            35      100      10   85     70      50      50***                            36      100      0    5      70      95      95***                            37      100      0    0      55      25      25***                            38      100      90   75     80      80      90***                            39      100      20   25     100     100     100***                           40      100      25   90     90      30      30***                            41      100      80   100    95      90      90***                            42      100      100  100    100     70      85***                            43      90       80   70     90      75      90***                            44      90       80   100    95      75      90***                            45      100      20   30     90      95      100***                           46      80       65   75     60      40      25***                            47      100      10   45     75      75      90***                            48      100      0    5      80      75      100***                           49      95       0    10     25      10      35***                            50      50       0    5      5       --       5***                            51      100      0    5      5       --      15***                            52      100      0    30     25      --      50***                            54      --       50   5      100     100**   100***                           57      25       0    45     55      --      90***                            58      100      --   85     50      25**    80***                            59      60       90   100    95      65**    95***                            60      0        0    0      20       0**    20***                            61      --       0    0      45      --      20***                            64       0*      0    0      5        0**    10***                            65       0*      0    0      10       0**    10***                            67       0*      0    5      45       5**    35***                            68       0*      0    25     70      20**    80***                            69       0*      0    0      5        0**    10***                            70       0*      0    25     95       0**    95***                            71      100*     0    20     100      0**    95***                            72      25*      0    55     75       0**    40***                            73      100*     100  100    100     10**    95***                            74       0*      0    0      15       0**    10***                            75      10*      0    10     80       0**    65***                            76       5*      0    25     50       0**    45***                            77       0*      0    20     30       5**    10***                            78       0*      0    50     80      30**    90***                            79       0*      0    0      10      --      --                               80       0*      0    5      75      --      --                               81       0*      0    5      0       --      --                               82      25*      25   75     80      --      --                               83      65*      25   75     95      --      --                               84      50*      25   60     100     --      --                               85       0*      0    35     90      --      --                               86      75*      20   75     100     --      --                               87      100*     0    30     95      --      --                               89      40*      0    0      35       0**    75***                            90       0*      0    75     80      90**    100***                           91      15*      0    85     65       5**    25***                            92      100*     90   85     100     100**   100***                           93       0*      0    5      15       0**    25***                            96       5*      0    20     70       0**    30***                            97       5*      0    20     55       5**    40***                            98       0*      0    0      20       0**    25***                            99       0*      0    5      0        0**     0**                             101     10*      0    20     15       0**    15***                            102      0*      0    5      0        0**     0***                            103      5*      0    15     30       0**    25***                            107      0*      0    5      15       0**    10***                            108     15*      0    40     60       5**    55***                            109      0*      0    0      0        0**     5***                            110     15*      0    25     65       5**    100***                           111      0*      0    0      0        0**     5***                            112      0*      0    5      10       0**    10***                            113     100*     0    100    100     10**    100***                           114      0*      0    10     70       0**    100***                           115      0*      0    0      10       0**    60***                            116      0*      0    5      40      15**    75***                            117      0*      0    0      5        0**    15***                            118      0*      0    0      40       0**    85***                            120     20*      15   45     5        0**    35***                            121      5*      5    10     45       0**    55***                            122     10*      50   80     90       0**    100***                           123      0*      0    5      35       0**    45***                            124      0*      0    5      25       0**    75***                            125     15*      0    5      45       0**    35***                            126     95*      5    35     25      55**    85***                            127      0*      0    15     0       --      --                               129     50*      0    30     90      95**    75***                            130     90*      0    20     95       5**    75***                            132     100*     0    50     100     20**    70***                            133      0*      0    20     80       5**    50***                            134      0*      0    30     75       0**    10***                            135     100*     0    15     95      85**    95***                            136     100*     85   100    100     70**    80***                            138      0*      0    0      10       9**     0***                            __________________________________________________________________________

Procedures for using the compounds of this invention as plant desiccantsand defoliants may be in accordance with the state of the art inconventional agricultural practice. The active ingredient(s) may beincluded in one or more formulations suitable for use in conventionalapplication equipment. Such formulations may be of several differentphysical and chemical types, any of which could be made by anyonefamiliar with the art. For instance, the active ingredient(s) may beformulated into a soluble or emulsifiable concentrate that is preparedby dissolving the active ingredient(s) in one or more suitable solvents,such as acetone, toluene, or other aliphatic or aromatic hydrocarbon, towhich a dispersing agent has been added. Alternatively, the activeingredient(s) may be formulated as a wettable powder by grinding it intoa fine powder and mixing it with an inactive powdered carrier, to whicha dispersing agent has been added. Typical inactive powdered carriersinclude attapulgite clay, vermiculite, talc, corn cob, activated carbon,mica and pyrophyllite. Alternatively, a wettable powder may beformulated by spraying a solution of the active ingredient(s) in organicsolvent onto the surface of an inactive powdered carrier as it isblended. The solvent is subsequently allowed to vaporize. Theconcentration of the active ingredient(s) in formulations of all typesmay vary widely, ranging from 0.1 to 95% active ingredient by weight.

Formulations bearing the active ingredient(s) may be dispersed in waterand applied to target plants. Surface active agents may be added to theapplied solution to increase its qualitative or quantitive range ofactivity. Suitable surface active agents are well known to those skilledin the art. Reference may be made to McCutcheon's Detergents andEmulsifiers (1980, Allured Publ. Co., Ridgewood, NJ) or to Hoffman et alin U.S. Pat. Nos. 2,614,916 (cols. 2 to 4) and 2,574,724 (cols. 3 and 4)for examples of appropriate surface active agents.

The most suitable dosage of application of the active ingredient(s) andthe type and amount of adjuvant substances to be added to the spraysolution will depend on a number of factors, including the specificbiological effect desired; the air and soil temperature; the quantityand intensity of rainfall before and after treatment; the soil type, pH,fertility and moisture content; the physiological condition and vigor ofthe target plants; the relative humidity and wind velocity of the airaround the crop; the extent and density of the foliar canopy of thetarget plant; the light quality, intensity and duration each day; andthe type and interval of previous and subsequent crop protectantchemical applications. All of these factors may have an influence on theefficacy of chemicals applied as harvest aids.

EXAMPLE 20

To illustrate the effectiveness of the described oxathiazines as cropplants desiccants, a 6000 ppm solution/suspension of active ingredientwas made up as described in Example 18. The chemicalsolutions/suspensions were applied to soybean.sup.(1) and cotton.sup.(2)plants as in Example 19. After 3 weeks in the greenhouse, the plantswere scored for leaf desiccation on a 0 to 100 scale, 0 being no damageand 100 being complete kill. A rating system suggested by Frans andTalbert (1977. Research Methods in Weed Science, 2nd edition, SouthernWeed Science Society) was used as a guide. The data obtained appear inTable 7.

                  TABLE 7                                                         ______________________________________                                        FOLIAGE DESICCATION ON COTTON AND                                             SOYBEAN AT 6000 PPM                                                           Compound        % desiccation                                                 No.             soybean  cotton                                               ______________________________________                                         1               5       35                                                    3              100      100                                                   5              100      100                                                   6              95       100                                                   7              40        0                                                    8              100      100                                                   9              100      100                                                  10              98       98                                                   11              100      100                                                  12               5       50                                                   13               0       100                                                  14              35        0                                                   15              85       95                                                   16              98       100                                                  17              40       15                                                   18              98       98                                                   19              95       100                                                  21              100      98                                                   24              100      100                                                  26              100      100                                                  27              100      100                                                  28              100      100                                                  29              100      100                                                  30              100      100                                                  31              100      50                                                   32              100      100                                                  33              100      100                                                  34              65       30                                                   35              100      95                                                   36              100      40                                                   37              95       35                                                   38              100      85                                                   39              100      100                                                  40              90       25                                                   41              100      100                                                  42              100      95                                                   43              85       20                                                   44              90       100                                                  45              75       60                                                   46              95       100                                                  47              90       85                                                   48              30       15                                                   49              30       20                                                   50              50       20                                                   51              15       80                                                   52              80       30                                                   54              30       10                                                   57              90        5                                                   58              95       100                                                  59              95        0                                                   60              35        0                                                   61              80        0                                                   64              25        0                                                   65              25        0                                                   57              90        5                                                   68              95       100                                                  69              45        0                                                   71              95       95                                                   72              85       25                                                   73              100      95                                                   74              30        0                                                   75              90        0                                                   76              55       90                                                   77              65        0                                                   79              65        5                                                   80              85        5                                                   81              65        0                                                   82              100      30                                                   83              100      90                                                   84              95       100                                                  85              80       15                                                   86              100      65                                                   87              95       10                                                   89              95       100                                                  90              90        5                                                   91              95       100                                                  92              95       100                                                  93              70       10                                                   96              95       100                                                  97              95       100                                                  98              25        0                                                   101             75       30                                                   103             70       20                                                   104             25       15                                                   108             55       10                                                   110             65        5                                                   111             55        0                                                   113             95       90                                                   114             30        0                                                   116             60        0                                                   118             20        0                                                   120              0       65                                                   121             35        5                                                   122             80       20                                                   124             25        0                                                   125             20        5                                                   126             85       100                                                  128              0       25                                                   129             85       100                                                  130             100      100                                                  131             55        0                                                   132             95       100                                                  133             95       100                                                  134             85       10                                                   135             95       100                                                  136             95       100                                                  137             35        0                                                   138             30       100                                                  ______________________________________                                    

EXAMPLE 21

To further illustrate the effectiveness of the described3-aryl-5,6-dihydro-1,4,2-oxathizines as plant defoliants, a 6000 ppmweight for volume (w/v) solution/suspension of tested chemical wasprepared by dissolving 600 mg chemical in 10 ml suitable organicsolvent. The solution was diluted to 100 ml with distilled watercontaining about 2000 ppm w/v surface active agent (e.g., "Tween 20").Twenty-five (25) ml of this 6000 ppm solution/suspension were diluted to100 ml with distilled water containing about 2000 ppm surface activeagent, resulting in a 1500 ppm solution/suspension of test chemical. Thechemical was applied to cotton plants (Gossypium hirsutum L. "Stoneville213") by immersion of the lower leaves. At the time of treatment, thecotton plants had 2 to 4 true leaves. After treatment, the plants werereturned to the greenhouse for about two weeks, at which time the plantswere evaluated for defoliation of the treated leaves. The scoring systemused: 1=5-25% defoliation, 2= 26-50%, 3=51-70%, 4=71-85%, 5=86-100%. Theresults appear in TABLE 8.

                  TABLE 8                                                         ______________________________________                                        COTTON DEFOLIATION AT 1500 PPM                                                Compound      Defoliation                                                     No.           Score                                                           ______________________________________                                         1            5                                                                3            5                                                                5            5                                                                6            5                                                                9            5                                                               10            5                                                               11            5                                                               12            5                                                               15            5                                                               16            2                                                               17            5                                                               18            5                                                               20            5                                                               23            2                                                               24            5                                                               26            5                                                               27            5                                                               28            5                                                               31            1                                                               33            3                                                               35            5                                                               36            5                                                               37            4                                                               38            5                                                               39            2                                                               41            5                                                               42            2                                                               44            3                                                               46            5                                                               51            3                                                               52            5                                                               55            1                                                               60            5                                                               63            3                                                               64            5                                                               65            5                                                               66            1                                                               67            4                                                               68            5                                                               69            1                                                               70            1                                                               71            2                                                               72            3                                                               73            4                                                               74            1                                                               75            2                                                               76            5                                                               77            2                                                               78            1                                                               82            2                                                               83            2                                                               84            5                                                               86            1                                                               87            1                                                               88            1                                                               89            5                                                               91            5                                                               92            5                                                               94            1                                                               95            2                                                               96            5                                                               97            5                                                               100           1                                                               105           1                                                               106           1                                                               108           1                                                               109           1                                                               110           1                                                               113           1                                                               114           1                                                               115           4                                                               116           4                                                               117           2                                                               118           5                                                               120           5                                                               121           2                                                               122           5                                                               124           2                                                               125           1                                                               126           5                                                               128           5                                                               129           5                                                               130           5                                                               131           2                                                               132           5                                                               133           5                                                               134           5                                                               136           5                                                               135           5                                                               137           2                                                               138           5                                                               ______________________________________                                    

Similar defoliating activity is observed with compounds of thisinvention wherein R is trichlorophenyl, R¹ is n-butyl, t-butyl or benzyland n is 0, 1 or 2.

In fungicidal applications, the chemicals may be applied directly toplants (i.e. seeds, foliage) or to soil in which plants are growing orto be grown, to protect against the harmful effects of pathogenic fungi.For example, the chemical may be applied to seeds by tumbling thechemical with the seeds, either alone or in admixture with a powderedsolid carrier. Typical powdered solid carriers are the various mineralsilicates, e.g., mica, talc, pyrophyllite, and clays. The chemical mayalso be applied to the seeds in admixture with a conventionalsurface-active wetting agent, with or without additional powdered solidcarrier, as by first wetting the mixture with a small amount of waterand then tumbling the seeds in the slurry. The surface-active wettingagents that may be used with the fungicide may be any of theconventional anionic, non-ionic, or cationic surface-active agents. Suchsurface-active agents are well known and reference is made to U.S. Pat.No. 2,546,724, columns 3 and 4, for detailed examples of the same. As aseed protectant, the amount of the chemical coated on the seeds will be1/4 to 12 oz. (7-350 g) per hundred lbs. (45.5 kg) of the seed. As asoil treatment for fungi, the chemical may be applied: (a) as a dust inadmixture with sand or soil a powdered solid carrier such as a mineralsilicate, with or without an additional surface-active wetting agent, tothe furrows simultaneously with the planting of the seeds; or (b) anaqueous spray, if desired including a surface-active or dispersingagent, or a surface-active or dispersing agent and a powdered solidcarrier, to the seed rows before, or with, or after planting the seeds.As a soil treatment, the amount of the chemical applied to the seed rowswill be from 0.1 to 10 pounds per acre (0.112 to 11.2 kg/ha) based onrows 2" (5 cm) wide and 2" (5 cm) deep a distance of 40" (102 cm) apart.Also, as a soil treatment, the chemical may be applied broadcast using asimilar dust or aqueous spray with an application rate of 1.0 to 100pounds per acre (1.12 to 112 kg/ha). As a foliage treatment, thechemical may be applied to growing plants at a rate of 1/4 to 10 poundsper acre (0.28 to 11.2 kg/ha). Such application is generally as anaqueous spray which also contains a surface-active or dispersing agent,with or without a powdered solid carrier or hydrocarbon solvent. Thesesprays usually are repeated at time intervals ranging from three days totwo weeks during the growing season. Typical formulations are as follows(all percentages are by weight):

    ______________________________________                                        (a)   Emulsifiable concentrate:                                               48.1%     Active Ingredient                                                   11.1%     Surfactant (e.g., polyoxyethylene sorbitan                                    monooleate)                                                         40.8%     Xylene                                                              100.0%    Total                                                               (b)   Wettable powder:                                                        75.0%     Active Ingredient                                                   2.0%      Triton (trademark) X-120                                            2.0%      Daxad (trademark) - 11                                              21.0%     Dixie clay                                                          100.0%    Total                                                               ______________________________________                                    

Triton X-120 is an alkylaryl polyether alcohol (9-10 moles polyethyleneoxide) in dry powdered form (40% active on an insoluble carrier). Theactive ingredient in Triton X-120 is Triton X-100, which is a liquidnonionic surfactant (isooctyl-phenylpolyethoxyethanol, obtained bycondensing the alkylphenylphenol with ethylene oxide). Daxad-11 ispolymerized sodium salt of alkylnaphthalene sulfonic acid (moreparticularly, the sodium salts of binaphthyl/methane sulfonic acidsobtained from naphthalene, sulfuric acid and formaldehyde, according toU.S. Pat. No. 1,336,759, Schmidt, Apr. 13, 1920).

EXAMPLE 22 Foliage Spray Treatment for Control of Established Bean Rustdisease caused by the fungus (Uromyces phaseoli)

Although many chemicals will serve to protect plants from disease, it isoften desirable to draw upon chemicals which have therapeutic propertiesto arrest the development of disease that has already becomeestablished. This example illustrates such properties.

Two hundred (200) milligrams of chemical were dissolved in 20 ml ofacetone and 60 mg of a surfactant such as Triton X-100. This preparationwas diluted with 80 ml distilled water giving a chemical suspension of2000 ppm. Further serial dilutions were prepared from this as desired.The chemical suspensions were sprayed on duplicate pots, each containingtwo snapbean plants which had, 48 hours prior to this, been inoculatedwith the bean rust fungus Uromyces phaseoli typica Arth. At the time ofthe chemical spray the bean plants had just begun to expand their firsttrifoliolate leaves. The test plants were then placed in a chamber for24 hours at 75° F. (24° C.) and 100% relative humidity. After this timethe plants were returned to the greenhouse. About 10 days later theplants were scored for disease control, with the results shown in TABLE9.

                  TABLE 9                                                         ______________________________________                                        Bean Rust Disease Control by Foliar Application at 1000 ppm                                  % DISEASE                                                      COMPOUND       CONTROL                                                        ______________________________________                                        29             95                                                             28              90*                                                            5             95                                                             ______________________________________                                    

EXAMPLE 23 Foliar Spray for Protecting Tomato Plants from infection bythe Early Blight Fungus, Alternaria solani Test procedure

One gram of the chemical to be tested was ground with three ml ofacetone and 50 mg of a non-ionic surface-active agent (Triton X-100).The acetone and surface-active agent are known to be inactive in thisbiological test. The mixture was diluted with water, giving suspensionscontaining 500 and 2000 ppm of the chemical. These suspensions weresprayed on duplicate six-inch (ca. 15 cm) tomato plants (variety Clark'sEarly Special) using a gun-type sprayer. Twenty-four hours later thetreated and untreated check plants were inoculated with a suspension ofAlternaria solani spores by means of a 20 second spray from an atomizersprayer (delivery rate 1 ml per second). The plants were then keptovernight in a controlled chamber at a temperature of 75° F. (24° C.)and 100% relative humidity. In the morning the plants were transferredto the greenhouse. Three days later the disease was scored by comparingthe number of disease lesions of the treated plants with the untreatedcontrol. The formula used to determine percent control is: ##EQU1##

The results are shown in TABLE 10.

                  TABLE 10                                                        ______________________________________                                        Control of Tomato Early Blight Disease                                        by Foliar Application at 1000 ppm.                                                           % DISEASE                                                      COMPOUND       CONTROL                                                        ______________________________________                                        4              92                                                             ______________________________________                                    

EXAMPLE 24 Foliar Spray for protecting plants from infection by the RiceBlast fungus, Piricularia oryza Test procedure

The chemical suspensions were prepared in manner described in Example23. The suspensions were sprayed on duplicate pots of clustered 7-dayold barley plants (variety Herta) using a gun-type sprayer. The plantswere then placed in a greenhouse together with untreated check plantsand allowed to dry. All test plants were inoculated with the fungus byspraying with a suspension of Piricularia oryzae spores (20,000-40,000spores/ml) to which a standard wetting agent has been added (Tween 20, 6drops/300 ml). After inoculation the plants were kept in atemperature-humidity control chamber for 24-48 hours at 70° F. (21° C.)to allow infection. Plants were then removed and placed in a 70° F. (21°C.) greenhouse to allow disease development. After 5 to 7 days, blastlesions appeared on the leaves. Disease control was evaluated by eithercounting lesions if infection was moderate or evaluating by a diseaserating scale of 0-6 with 6 being severe disease. Percent control wascomputed by comparing the treatment scores with that of the untreatedcontrol (TABLE 11).

                  TABLE 11                                                        ______________________________________                                        Control of Piricularia Blast Disease                                          On Barley by Foliar Application                                                                       % DISEASE                                             COMPOUND        PPM     CONTROL                                               ______________________________________                                        32              1000    87                                                     4              500     84                                                    21              1000    83                                                    65              500     85                                                    77              500     85                                                    91              500     100                                                   ______________________________________                                    

EXAMPLE 25 Antifungal activity as demonstrated by laboratory tests onfungus cultures

The chemicals of the invention were dissolved in acetone, and applied at500 ppm to 13 mm antibiotic testing discs by dipping the discs in thetest solutions. After drying, the treated discs were placed on an agarplate (4 per plate), then 7 mm plugs of mycelium of various fungi wereplaced on the center of the discs in such fashion that the fungus matwas in direct contact with the treated disc. The fungitoxic activity ofthe chemicals was measured by comparing growth (colony radius) of thefungus on the treated discs with that on untreated controls. Colonyradius was measured when untreated controls reaches 80-90% of the areaavailable for growth on the plates. The fungi tested were Alternariasolani (A), Fusarium oxysporum (F), Pythium sp. (P) and Sclerotiumrolfsii (S). The results are shown in TABLE 12.

                  TABLE 12                                                        ______________________________________                                                   % INHIBITION @ 500 ppm                                             COMPOUND     A      F          P    S                                         ______________________________________                                         6           65     --          90  --                                         8           50     --         100  90                                         9           50     --         100  --                                        35           --     --          60  90                                        47           70     --         --   --                                        48           70     --         --   --                                        78           10     --         --   100                                       29           75     70         100  30                                        32           30     70         100  55                                        41           80     --         100  80                                        42           80     --         100  80                                        36           30     55         100  70                                        28           85     70         100  40                                         5           100    95          80  100                                       19           95     90         100  95                                        46           95     95         100  80                                        15           75     70         100  45                                        52           100    --         100  65                                        21           65     45          95  55                                        33           100    100        100  95                                        38           75     65         100  100                                       38           75     --         100  100                                       53           100    --         100  65                                        82           75     --         100  65                                        84           80     --         100  65                                        86           100    --         100  85                                        91           65     --          90  55                                        43           --     --         100  55                                         4           100    20          50  --                                        59           80     --         --   40                                         7           20     --         100  50                                        58           --     --          90  45                                        17           80     70          30  30                                        24           95     90         100  95                                        21           45      5          85  25                                        44           --     100        100  60                                        53           90     --          60  50                                        57           65     --         100  60                                        65           95     --          75  85                                        77           75     --          80  60                                        81           60     --          70  75                                        85           90     --         100  65                                        ______________________________________                                    

EXAMPLE 26

Foliar Spray for protecting plants from infection by the peanut leafspotfungus, Cercospora arachidicola.

TEST PROCEDURE

The chemical suspensions were prepared in a manner described in Example23. The suspensions were sprayed on duplicate pots of clusteredone-month old peanut plants (variety Florrunner), using a gun-typesprayer. After the plants were dried, they were inoculated with thefungus by spraying with a suspension of Cercospora arachidicola spores(20,000 spores/ml) to which a standard wetting agent had been added(Tween 20, 6 drops/300 ml). Plants were placed in temperature-humiditycontrolled chamber for 24-48 hours at 70° F. (21° C.) to allow infectionto be initiated. Plants were then removed from the chamber andtransferred to a 70° F. (21° C.) greenhouse to allow diseasedevelopment. After about 21 days, symptoms had developed on theleaflets. Disease control was evaluated by counting lesions if infectionwas moderate or evaluating by a disease rating scale of 0-6, with 6being severe disease. Percent control was computed by comparing thetreatment scores with that of the untreated control. The results areshown in TABLE 13.

                  TABLE 13                                                        ______________________________________                                        Control of Cercospora Leafspot Disease of                                     Peanuts by Foliar Application                                                                         % DISEASE                                             COMPOUND         PPM    CONTROL                                               ______________________________________                                        65               1000   95                                                                      500   90                                                    77               1000   93                                                                      500   95                                                    84               1000   100                                                                     500   100                                                   67               1000   80                                                                      500   45                                                    68               1000   85                                                                      500   80                                                    72               1000   78                                                                      500   78                                                    73               1000   80                                                                      500   75                                                    75               1000   50                                                                      500   50                                                    82               1000   90                                                                     5000   80                                                    83               1000   90                                                                      500   95                                                    90               1000   96                                                                      500   92                                                    95               1000   55                                                                     5000   55                                                    97               1000   80                                                                      500   90                                                    ______________________________________                                    

What is claimed is:
 1. A compound of the formula: ##STR10## wherein n=0,1 or 2R¹ =hydrogen, C₁ -C₄ linear or branched alkyl or benzyl R=phenylor naphthylphenyl substituted with 1-2 of the following groups:hydroxylhalo C₁ -C₁₂ alkyl C₅ -C₆ cycloalkyl trihalomethyl phenyl C₁ -C₅ alkoxyor alkylthio tetrahydropyranyloxy phenoxy C₂ -C₅ alkylcarbonylphenylcarbonyl C₁ -C₄ alkylsulfinyl C₁ -C₄ alkylsulfonyl carboxy or itsalkali metal salt C₂ -C₅ alkoxycarbonyl C₂ -C₅ alkylaminocarbonylphenylaminocarbonyl tolylaminocarbonyl morpholinocarbonyl amino nitrocyano dioxolanyl pyridinyl thienyl provided n is 0 or 1 furanyl furanylsubstituted with 1-3 of the following groups:C₁ -C₄ alkyl C₂ -C₅alkoxycarbonyl.
 2. A compound as in claim 1 in whichR¹ =hydrogen or C₁-C₄ linear or branched alkyl R=phenyl;phenyl substituted with 1-2 of thefollowing groups:F, Cl, Br except 2-Cl or 2,4-Cl₂ if n is 2 C₁ -C₄except p-t-alkyl if n is 0 CF₃ phenyl, except if n is 2 C₁ -C₅ alkoxy C₂-C₅ alkylcarbonyl C₂ -C₅ alkoxycarbonyl, except 4-alkoxycarbonyl if n is0 amino nitro cyano; 3- or 4-pyridinyl provided n is 0 or 1 thienylprovided n is 0 or 1 furanyl; furanyl substituted with 1-3 of thefollowing groups:methyl C₂ -C₃ alkoxycarbonyl.
 3. A compound as in claim1 in whichR¹ =hydrogen or methyl R=phenyl, provided n is 0 or 1phenylsubstituted with 1 or 2 of the following groups:F, Cl, Br, except 2-Clor 2,4-Cl₂ if n is 2 n-C₁ -C₄ alkyl CF₃ C₁ -C₂ alkoxy C₂ -C₅alkylcarbonyl, provided n is 1 C₂ -C₃ alkoxycarbonyl, provided n is 1 or2 nitro cyano; 3- or 4-pyridinyl provided n is 0 or 1; thienyl providedn is 0 or 1 furanyl; furanyl substituted with 1-3 methyl groups providedn is 1 or
 2. 4. The compound of claim 1 wherein R¹ is hydrogen, n is 1and R is phenyl.
 5. The compound of claim 1 wherein R¹ is hydrogen, n is1 and R is 3-fluorophenyl.
 6. The compound of claim 1 wherein R¹ ishydrogen, n is 1 and R is 2-furanyl.
 7. The compound of claim 1 whereinR¹ is hydrogen, n is 1 and R is 3,5-dichlorophenyl.
 8. The compound ofclaim 1 wherein R¹ is hydrogen, n is 1 and R is3-(methoxycarbonyl)phenyl.
 9. The compound of claim 1 wherein R¹ ishydrogen, n is 1 and R is 4-chlorophenyl.
 10. The compound of claim 1wherein R¹ is hydrogen, C₁ -C₄ linear or branched alkyl or benzyl, n is0, 1 or 2 and R is phenyl substituted with 3-Cl, 3-Br, 3-F,2,5-dimethyl, 3-trifluoromethyl, 3-nitro or 3-cyano.
 11. The compound ofclaim 10 wherein n is 1, R¹ is hydrogen and R is 3-fluorophenyl.
 12. Amethod for controlling weeds comprising applying to a locus at which itis desired to control the weeds a herbicidally effective amount of acompound as in claim 1 in which R¹ is hydrogen, C₁ -C₄ linear orbranched alkyl or benzyl; n is 0, 1 or 2; andR=phenyl or naphthyl;phenylsubstituted with 1-2 of the following groups:halogen except 2-Cl if n is2 C₁ -C₁₂ alkyl C₅ -C₆ cycloalkyl trihalomethyl C₁ -C₈ alkoxy except C₄-C₈ alkoxy if n is 0 or 2 phenoxy tetrahydropyranyloxy C₁ -C₈ alkylthioC₁ -C₄ alkylsulfinyl C₁ -C₄ alkylsulfonyl C₂ -C₅ alkylcarbonyl providedn is 0 or 1 carboxyl or its alkali metal salt 2- or 3-(C₂ -C₅alkoxycarbonyl) C₂ -C₅ alkylaminocarbonyl 4-(C₂ -C₅ alkoxycarbonyl)provided n is 0 or 1 morpholinocarbonyl amino nitro cyano dioxolanyl;4-pyridinyl provided n is 0 or 1; thienyl provided n is 0 or 1; furanyl;furanyl substituted with 1-3 of the following groups:C₁ -C₄ alkyl C₂ -C₅alkoxycarbonyl.
 13. A method as in claim 12 in which R¹ is hydrogen orC₁ -C₄ linear or branched alkyl andif n=0, 1 or 2, R=phenyl substitutedwith 1-2 of the following groups:3-CF₃ ; n-C₁ -C₄ alkyl provided theyare in 3- or 4-position; 4-Cl; 3-pyridinyl; furanyl; furanyl substitutedwith 1-3 of the following groups:methyl; C₂ -C₃ alkoxycarbonyl; if n=0or 1, R=phenyl;phenyl substituted with 1-2 of the following groups:F orCl; trifluoromethyl; thienyl; if n=1, R=phenyl substituted with 1-2 ofthe following groups:4-Br; C₁ -C₅ alkoxy; 3-nitro; 4-CF₃ ; 3-cyano. 14.A method as in claim 13 in which,R¹ is hydrogen or methyl and if n=0, 1or 2, R=phenyl substituted with 1-2 of the following groups:4-Cl 3- or4-(n-C₁ -C₃ alkyl); if n=1 or 2, R=2-furanyl; if n=1, R=phenyl;phenylsubstituted with 1-2 of the following groups:3-Cl or 3-F 4-CF₃ 3-methoxy3-nitrio 4-(C₁ -C₄ alkyl); 2-thienyl; if n=0 or 1, R=3-pyridinyl; ifn=0, R=phenyl substituted with one of the following groups:2,4-Cl₂ 2-Cl3-Cl 4-F 2-Cl-6-F.
 15. A method as in claim 12 in which said compound is3-phenyl-5,6-dihydro-1,4,2-oxathiazine 4-oxide.
 16. A method as in claim12 in which said compound is3-fluorophenyl-5,6-dihydro-1,4,2-oxathiazine 4-oxide.
 17. A method as inclaim 12 in which said compound is2-furanyl-5,6-dihydro-1,4,2-oxathiazine 4-oxide.
 18. A method for makinga compound as in claim 1 comprising the steps(1) reacting a compound ofthe formula RCS₂ CH₂ CH₃, wherein R is as defined in claim 1, with H₂NOH, and (2) treating the equilibrium product of step 1 with a compoundhaving the formula R¹ C(X)H--C(X)H₂ wherein R¹ is hydrogen, C₁ -C₄linear or branched alkyl or benzyl; and X is halogen; in the presence oftwo equivalents of base.